PERUGIA, Italy — Prosecutors began closing arguments in a bid to uphold the murder conviction of American student Amanda Knox in the 2007 slaying of her roommate, with Knox’s family hopeful that a review of DNA evidence during the long appeals trial will lead to her release.

Prosecutor Giancarlo Costagliola opened the arguments on Friday before a packed courtroom, the final phase of the 10-month appeals in the highly contentious case. A verdict is expected in early October, after the defense, the victim’s family and probably Knox herself make their case.

Knox and her one-time boyfriend, Raffaele Sollecito of Italy, were convicted of sexually assaulting and murdering Knox’s British roommate, Meredith Kercher. Knox was sentenced to 26 years in prison; Sollecito to 25.

The father of Amanda Knox said he was hopeful that a review of DNA evidence casting doubt on much of the genetic evidence used to convict Knox will help his daughter overturn the conviction.

Curt Knox, in an interview with The Associated Press in Perugia on the eve of the closing arguments, said he was grateful to the appellate court for having granted the review.

The appeals trial has focused largely on DNA evidence used to convict the defendants. Without a clear motive or convincing witnesses, the DNA evidence is crucial, and much of the appeals outcome hinges on it.

Knox’s defense received a boost when a court-ordered independent review found that much of the genetic evidence was unreliable and possibly contaminated.

“We’re hopeful,” Curt Knox told the AP. “I believe the real truth is really coming out.”

In the first trial, prosecutors maintained that Knox’s DNA was found on the handle of a kitchen knife believed to be the murder weapon, and that Kercher’s DNA was found on the blade. They said Sollecito’s DNA was on the clasp of Kercher’s bra as part of a mix of evidence that also included the victim’s genetic profile.

The independent review challenged both findings. It said police had made glaring errors in evidence collecting and that below-standard testing raised doubts over the attribution of DNA traces, both on the blade and on the bra clasp, which was collected from the crime scene several weeks after the murder.

“We were not surprised with the results because this is what our defense experts were telling us all along,” Curt Knox said. “I’m very thankful that the appeals court had the courage to authorize that independent review.”

During their closing arguments, prosecutors were seeking to persuade the jury that the evidence can stand, and defend the original investigation — as they have during some fiercely debated hearings focusing on the review.

The prosecutors have argued that the 21-year-old Kercher was the victim of a drug-fueled sex assault. Her body was found in the apartment she shared with Knox, her throat slit.

In the original trial, the prosecutors had sought life sentences — Italy’s stiffest punishment. Like the defendant, they have also appealed the lower court’s verdict, as they can in Italy.

The prosecutors are also expected to illustrate to the court what they say are other pieces of evidence that point to Knox and Sollecito, such as bloody footprints found in the house that are compatible with those of the defendants. They will likely remind the court that Knox initially gave contradicting accounts on the night of the murder, at one point accusing a Congolose man who was briefly arrested as a result of that claim, and later cleared.

Knox maintains she acted under police pressure when she was questioned in the aftermath of the killing.

The American student, now 24, maintains she spent the night of the murder at Sollecito’s house, watching a movie on his computer. But the prosecution argues that there was no sign of the defendant using his computer during the hours of Kercher’s murder.

Next week, a lawyer representing the Kercher family and then the defense lawyers will make their closing arguments. Knox herself is expected to address the court in a final appeal to proclaim her innocence.

A third person, Rudy Hermann Guede of the Ivory Coast, also has been convicted of Kercher’s murder in a separate proceeding. Italy’s highest criminal court has upheld Guede’s conviction and his 16-year-prison sentence. Guede denies wrongdoing.